With the recent increasing demand for laser metalworking, semiconductor laser devices are required to have higher output.
FIG. 15 is a schematic configuration view of laser diode 900 known in the art. As shown in FIG. 15, laser diode 900 includes upper electrode 901, insulating member 902, LD chip 903, submounts 904 and 905, heat sink 906, and wire 907. Heat sink 906 is mounted with a laminated body of upper electrode 901 and insulating member 902, and a laminated body of LD chip 903 and submounts 904 and 905.
The upper surface of LD chip 903 is joined to upper electrode 901 (negative electrode) via wire 907. The lower surface of LD chip 903 is joined to a positive electrode (not shown) via submounts 904 and 905. Heat sink 906 includes a flow channel for cooling water to improve cooling efficiency (see, e.g., Japanese Unexamined Patent Application Publication No. 2008-172141).
In laser diode 900 known in the art, the current path for the negative electrode is wire 907, while the current path for the positive electrode is not clearly described. Thus, when laser diode 900 has current paths with high electrical resistance, LD chip 903 is supplied with only a limited current, failing to achieve high laser output.